Aerosols containing low molecular weight radionuclides such as 99mTc-diethylenetriamine pentaacetate will be inhaled by patients with pulmonary edema due to congestive heart failure or lung damage. The removal of the radionuclide from the lung will be followed by a portable scintillation camera over the next 20 minutes. A correlation will be sought between epithelial damage and increased rates of radionuclide clearance. The effect of hypoxia and pulmonary edema upon endothelial carbonic anhydrase and angiotensin converting enzyme will be determined in a perfused rabbit lung preparation. The protective effect of albumin in hemodynamic and non-hemodynamic pulmonary edema will be studied in a similar preparation.